SURRY, Va. (AP) _ A water line ruptured and released hot water and steam Tuesday at Virginia Power's Surry nuclear power plant, injuring eight construction workers, authorities said. Five workers were critically burned.

There was no release of radiation, said Janet Clements of the state Office of Emergency Services.

The 2:21 p.m. accident in the plant's turbine building did not involve radioactive material, although the reactor, Unit No. 2, automatically shut down when the accident occurred, said Mark G. Lazenby, a Virginia Power spokesman.

The pipe, about 18 inches in diameter, carries heated water to one of two main pumps that deliver it to three steam generators that produce electricity, Lazenby said.

Officials had not determined what caused the pipe to fail, Jack Wilson, the utility's manager of nuclear operations support.

An alert was declared 19 minutes later but was canceled at 4:23 p.m., he said. In nuclear industry terminology, an alert is the third highest of four accident classifications ranging from a ''general emergency'' down to an ''unusual event.''

''It was a big boom,'' said Sue Scarborough, who was working on the floor above the pipe when it burst. ''First you heard the breaker trip, and then the pipe burst.''

Three of the injured workers were taken by helicopter to Norfolk General Hospital. Three others were taken by ambulance to Riverside Hospital in Newport News, and two later were flown to Norfolk General. The two other injured workers suffered minor injuries and did not require hospitalization, Lazenby said.

Anne Adler, a spokeswoman for Norfolk General, said the five workers brought there had burns over more than 50 percent of their bodies.

''All of these people were exposed to significant amounts of steam, '' Yeiser said. ''It's a bad type of burn. It's just like being submerged in boiling water.''

Virginia Power spokesman Bill Hall said said the workers were peforming modification and maintenance work near the pipe that burst but were not working on the pipe itself.

Ken Clark, a spokesman for the Nuclear Regulatory Commission regional office in Atlanta, said the NRC was sending a team of inspectors to the Surry station to investigate.

The Surry plant, which has two nuclear reactors, is about 40 miles northwest of Norfolk on the south side of the James River across from the Jamestown settlement.